The present invention relates to connectors for joining extruded metal lengths and, more particularly, to such a connector which is releasable and of single piece construction. Among the uses of the connectors are corner keys for metal picture frames.
The U.S. patent to Herbert, No. 3,534,490, discloses a picture frame construction employing extruded members having rearwardly opening channels for receiving corner keys connecting the members. Small set screws are threaded through the corner keys to secure the connections. While this frame construction provides an attractive and widely used frame, the use of small set screws in joining the frame sections together presents disadvantages as such screws are difficult to handle and easily lost during assembly of the frame. Also, with screw connections, it is possible for the screw to loosen with the possible opening of the frame corners with subsequent damage to the glass and/or artwork contained in the frame.
The use of corner keys for picture frames which have spring tabs for locking the frame sections together has been proposed. Typical connectors of this type are shown in the U.S. patents to Tursky, No. 2,078,744; Fernberg et al, No. 3,191,243; and Kapstad, No. 3,955,298. These connectors, however, are not readily releasable.
It is a primary object of the present invention to provide a connector for extruded sections such as picture frame members which is of single piece construction, eliminating the necessity of using separate screws, and which is readily releasable when desired.
A further object of the invention is the provision of such a connector which is economical to manufacture.